JACKSON, Mississippi --Mississippi Gov. Phil Bryant issued an emergency declaration Monday for 36 of the state's 82 counties to speed up response to a storm that's expected to bring snow and ice to central and southern parts of the state starting early Tuesday.

The Highway Patrol was sending 20 extra troopers to the southern part of the state, and crews from the Mississippi Department of Transportation were putting salt brine, sand or liquid magnesium on highways and bridges in the area that could see dangerous accumulation. It runs from the I-20 corridor that runs through Vicksburg, Jackson and Meridian, on down to the Gulf Coast.

"As always in these types of situations, we're hoping for the very best conditions and planning for the worst," Bryant said during a briefing late Monday at the Mississippi Emergency Management Agency headquarters in Pearl.

Bryant said 26 school districts had already canceled Tuesday classes because of concerns about slick roads, and other closures were possible.

The National Weather Service predicts ice accumulations up to three-quarters of an inch along the Gulf Coast; snow accumulations of up to 4 inches along the U.S. Highway 84 corridor; and up to an inch of snow along and south of the Interstate 20 corridor.

A hard freeze warning was out for portions of north Mississippi from Monday night until mid-day Wednesday. The weather service warned temperatures were expected to fall into the upper teens Monday and remain below freezing on Tuesday and fall back in to the teens Tuesday night. Forecasters said temperatures would not rise above freezing until Wednesday afternoon.

MEMA director Robert Latham said people should make their own preparations before the storm hits.

"There's nothing like an ice storm. Response to it is challenging," Latham said, recalling a 1994 ice storm that snapped thousands of trees and caused extended power outages in north Mississippi.

"If you're not ready before it happens, there's not a lot you can do once it starts," Latham said.

Dick Hall, the central district transportation commissioner, said salt brine and other material to sprinkle on highways and bridges was being moved from north Mississippi, where ice is not predicted, to areas in the south that are more likely to see accumulation.

"If you don't have a reason to be on that highway, a very important reason, don't get on it," Hall said. "Don't get on those roads."